Since its 1977 launch, NASA’s Voyager 1 spacecraft has travelled farther than any other piece of human technology. It is also the only human-made object to have entered interstellar space. More recently, the agency’s New Horizons mission flew past Pluto on July 14, giving us our first close-up lo...
For more than 50 years, scientists have debated what turns particular oxide insulators, in which electrons barely move, into metals, in which electrons flow freely.